• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.277-280
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• 2011

We studied the relative stability and atomic structure of five $C_{20}^{2+}$ isomers obtained by two-electron ionization of a $C_{20}$ cage (the smallest fullerene). All the isomers are bond-stretch isomers, i.e., they differ in bond length. In particular, in one of the isomers with Ih symmetry, all the bond lengths are equal. Full geometry optimizations of the dipositive ion $C_{20}^{2+}$ were performed using the hybrid density functional (B3LYP/6-31G(d)) methods. All isomers were found to be true minima by frequency analysis at the level of B3LYP/6-31G(d) under the reinforced tight convergence criterion and a pruned (99,590) grid. The zero-point correction energy for the cage bond-stretch isomers was in the increasing order $D_{2h}<C_{2h}<C_2<T_h<I_h$ of $C_{20}^{2+}$. The energy difference among the isomers of cage dipositive ions was less than that among neutral cage isomers. Our results suggest that these isomers show bond-stretch isomerism and that they have an identical spin state and an identical potential energy curve. Although the predominant electronic configurations of the isomers are similar, the frontier orbital characteristics are different, implying that we could anticipate an entirely different set of characteristic chemical reactions for each type of HOMO and LUMO.

• Journal of Korean Neurosurgical Society
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• 제30권7호
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• pp.883-890
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• 2001

Objectives : An in vitro biomechanical study of posterior lumbar interbody fusion(PLIF) with threaded cage using two different approaches was performed on eighteen functional spinal units of bovine lumbar spines. The purpose of this study was to compare the segmental stiffnesses among PLIF with one long posterolateral cage, PLIF with one long posterolateral cage and simultaneous facet joint fixation, and PLIF with two posterior cages. Methods : Eighteen bovine lumbar functional spinal units were divided into three groups. All specimens were tested intact and with cage insertion. Group 1(n=12) had a long threaded cage($15{\times}36mm$) inserted posterolaterally and oriented counter anterolaterally on the left side by posterior approach with left unilateral facetectomy. Group 2(n=6) had two regular length cages($15{\times}24mm$) inserted posteriorly with bilateral facetectomy. Six specimens from group 1 were then retested after unilateral facet joint screw fixation in neutral(group 3). Likewise, the other six specimens from group 1 were retested after fixation with a facet joint screw in an extended position(group 4). Nondestructive tests were performed in pure compression, flexion, extension, lateral bending, and torsion. Results : PLIF with a single cage, group 1, had a significantly higher stiffnesses than PLIF with two cages, group 2, in left and right torsion(p<0.05). Group 1 showed higher stiffness values than group 2 in pure compression, flexion, left and right bending but were not significantly different. Group 3 showed a significant increase in stiffness in comparison to group 1 for pure compression, extension, left bending and right torsion(p<0.05). For group 4, the stiffness significantly increased in comparison to group 1 for extension, flexion and right torsion(p<0.05). Although there was no significant difference between groups 3 and 4, group 4 had increased stiffness in extension, flexion, right bending and torsion. Conclusion : Posterior lumbar interbody fusion with a single long threaded cage inserted posterolaterally with unilateral facetectomy enables sufficient decompression while maintaining a majority of the posterior elements. In combination with a facet joint screw fixation, adequate postoperative stability can be achieved. We suggest that posterolateral insertion of a long threaded cage is biomechanically an ideal alternative to PLIF.

• 수산해양기술연구
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• 제47권3호
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• pp.214-221
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• 2011

This study was performed to develop a video based system which can be used to measure the averaged fish size in a non-intrusive fashion. The design was based on principles of simple stereo geometry, incorporated fish dimensions weight relationships and took into consideration fish movement to lower system costs. As the fish size is an important factor that impacts the economy of an aquaculture enterprise. Size measurements, including fork length, width or height, girth, thickness and mass, can be used to determine fish condition in the fish farm, so the averaged fish size of fish cage needs to consistently monitor in open ocean aquaculture cage. A precision of ${\pm}3%$ for replicate length measurements of a 60cm bar is obtained at distances between 2.0 and 6.0m, and the mean fork length and mean swimming speed of bluefin tuna were estimated to 48.8cm and 0.78FL/s, respectively.

• 한국패류학회지
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• 제30권3호
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• pp.227-234
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• 2014

본 연구는 해상가두리의 먹이공급비율에 따른 성장 및 생존율을 조사하고, 실내육상양식의 먹이 공급율과의 비교를 통해 국내 주요 북방전복 양성방법인 해상가두리와 함께 실내 사육 수조의 적정 천연먹이의 공급율을 제안하여 북방전복 생산성 향상을 유도하고자 실시하였다. 먹이공급율은 전복 어체중량을 기준으로 일간공급율 (daily feeding rate, DFR) 5, 10, 15, 20% (5DFR, 10DFR, 15DFR, 20DFR) 를 설정하여, 해상가두리와 실내육상수조에서 2반복으로 13개월간 실시하였다. 해상가두리에서 사육한 전복 (최초 수용 시 평균각장 $54.18{\pm}7.39mm$) 성장에서 각 장과 각폭의 절대성장율 (absolute growth rate, ARG), 일간 성장율 (daily growth rate, DGR) 및 특수생장율 (specific growth rate, SGR) 과 중량의 증중률 (weight gain, WG), 일간증중률 (daily weight gain, DWG) 및 특수증중률(specific weight gain, SWG), 그리고 생존율에서 20DFR이 유의적으로 낮았다 (P < 0.05). 실내육상수조에서 사육한 전복 (최초 수용 시 평균각장 $49.70{\pm}2.28mm$) 의 각장, 각폭의 ARG, DGR, SGR과 중량의 WG, DWG, SWG에서는 5DFR, 10DFR이 유의적으로 높았고 (P < 0.05), 생존율은 20DFR이 유의적으로 낮았다 (P < 0.05). 따라서 해상가두리와 실내육상수조 전복양식 자연먹이의 일간 공급율은 성장과 생존율, 그리고 경제적 측면까지 고려하면 어체중량의 5-10%에서 공급해야 한다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.173-173
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• 2006

We have explored a strategy to control the supramolecular nano-structures self-assembled from rigid segments through attachment of flexible chains through microphase separation and anisotropic arrangement. Supramolecular structures formed by self-assembly of rigid building blocks can be precisely controlled from 1-D layered, 3-D bicontinuous cubic to 2-D cylindrical structures by systematic variation of the type and relative length of the respective blocks. Furthermore, depending on the individual molecular architectures, rigid building blocks self-assemble into a wide range of supramolecular structures such as honeycomb, disk, cylinder, helix, tube, barrel stave, and nano-cage.

• Journal of Animal Science and Technology
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• 제51권5호
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• pp.421-426
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• 2009

본 연구는 산란계의 사육공간의 크기별 발성음의 특성을 파악하기 위해 하이라인브라운(Hy-Line Brown) 80주령의 산란계를 대상으로 2008년 10월부터 2009년 2월까지의 기간 동안 발성음을 수집 및 녹음하였다. 산란계의 사육 케이지는 무항생제 축산물 사육밀도조건을 만족하는 0.0231 $m^3$ (0.3m ${\times}$ 0.14m ${\times}$ 0.55m)을 개체당 사육공간의 기준(control)으로 하고, 좁은 공간(small, 0.21m ${\times}$ 0.14m ${\times}$ 0.55m)과 넓은 공간(large, 0.3m ${\times}$ 0.3m ${\times}$ 0.55m) 등의 3가지 유형으로 구분하였다. 하루 3회, 각각 1시간씩 디지털 녹음기(PMD-650, Marantz)와 마이크(MKH 416P48, RF Condenser Mic.)를 이용하여 발성음을 녹음하여 분석을 실시하였다. 발성음의 스펙트로그램을 비교한 결과 케이지의 크기별로 차이가 있는 것으로 나타났으며, 스펙트럼을 비교한 결과 역시 차이가 있었다. 또한 발성음의 주파수, 강도 및 길이 역시 통계적으로 유의한 차이를 나타내었다. 본 연구를 통해 산란계의 사육공간과 발성음 사이에는 깊은 관련이 있었으며, 사육공간에 의한 스트레스의 정도를 파악하기 위해 발성음은 매우 유용할 것으로 판단된다.

• 한국잠사곤충학회지
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• 제54권1_2호
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• pp.17-22
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• 2016

사육환경은 아메리카동애등에(Hermetia illucens) 의 산란에 직접적으로 영향을 준다. 본 연구에서는 아메리카동애등에 성충사육상의 크기와 산란처에 따른 산란 선호성을 조사하였다. 성충사육상의 높이를 2 ｍ로 고정시키고 가로 세로의 길이만 다르게 제작하였으며 20,000 개체의 성충을 사육상에 투입하였다. 평균 난괴수는 가로, 세로 길이가 $4{\times}4m$인 사육상에서 평균 895.4 난괴, $2{\times}1m$ 사육상에서 876.3 난괴 그리고 $1{\times}1m$ 사육상에서 62.3난괴를 산란하였다. 아메리카동애등에 성충사육상의 재질에 따른 산란난괴수를 비교한 결과 모기장망사육상에서는 820.7 난괴를 산란하였고 비닐재질사육상에서는 604.3 난괴를 산란하였다. 성충산란처의 종류별로는 갈색골판지에 평균 41.0 난괴 녹색 플로랄폼은 326.6 난괴를 산란하였으며, 녹색테이프를 붙인 골판지에는 135.2 난괴를 산란하였다. 산란처로 플로랄폼과 갈색 골판지에 플로랄폼을 겹친 산란처에서는 유사한 산란결과로 평균 64.7과 57.7난괴를 산란하였다. 산란처 구멍의 직경이 6 mm와 4 mm에서는 29.0과 48.2 난괴를 산란했다.

• 한국수산과학회지
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• 제38권2호
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• pp.129-136
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• 2005

The movement ranges and diurnal behavior of the rockfish (Sebastes schlegeli) sonic tagged externally were measured by the acoustic telemetry in the marine ranching area of Tongyoung on 20 to 26 March and 4 October to 3 November, 2003. The results of study are as follows: 1. Two cage cultured fishes (body length: $30-34{\cal}cm$) were released the point where located approximately $250{\cal}m$ from the caught point on 30 March, 2003. They moved to the south $500{\cal}m$ away Sojangdudo and stayed within a $500{\cal}m$ radius of the position during the study. 2. Three wild fishes (body length: $28-32{\cal}cm$) were released around the caught point on 4 and 8 October, 2003. It was often measured that tagged fishes moved out the $500{\cal}m$ radius of released point for a week after release. After several days, the movement range tended to be reduced. Finally, they stayed within the $250{\cal}m$ radius of released point. 3. There was no significant difference of diurnal behavior of the rockfish between the cage cultured and the wild fishes. The movement range, however, for the night-time was a little wider than for the day-time.

• 한국수산과학회지
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• 제14권4호
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• pp.221-226
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• 1981

영일만에서 1980년 4월과, 1981년 4월 및 5월에 채묘하여 1981년 7월까지 양성한 결과와 1979년 11월에 자연산을 수집하여 1981율 7월까지 양성한 것을 요약하면 다음과 같다. 1. 양식 가리비는 채묘후 약 1년 3개월 후에 각장이 약 6cm, 2년 후에 9.3cm, 2년 7개월 후에 10cm, 약 3년 2개월 후에 11.2cm, 약 3년 7개월 후에 11.3cm로 성장하였다. 2. 4월에 채묘한 것이 5월에 채묘한 것에 비해 각장의 크기가 7월 중순까지 약 2배 정도 더 컸다. 3. 9월 초에 중간 육성망에 옮겨 양성한 치패가 채묘망에서 관리를 하지 않고 양성한 것에 비해 성장이 훨씬 양호하였다. 4. 치패부터 수하식으로 양성하는 것이 바닥에서 양성한 것이나, 자연산을 수집하여 수하양성한 가리비에 비에 약 1년 이상 성장이 빨랐다. 5. 가리비 성패의 패각근 중양은 각장이 커짐에 따라 증가하는 경향이었는데 15g(각장 $60\sim70mm$)에서 94.13g(각장 $130\sim140mm$)의 값을 보였다.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.106-113
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• 2014

Rotor eccentricity is one of the major factors that directly influence the security of horizontal electrical machines, and the critical speed of the shaft has a close relationship with vibration. This paper deals with the influence of thermal expansion on the rotor eccentricity and critical speed in large dry submersible motors. The dynamic eccentricity (where the rotor is still turning around the stator bore centre but not its own centre) and critical speed of a three-phase squirrel-cage submersible induction motor are calculated via hybrid analytical/finite element method. Then the influence of thermal expansion is investigated by simulation. It is predicted from the study that the thermal expansion of the rotor and stator gives rise to a significant air-gap length decrement and an inconspicuous slower critical speed. The results show that the thermal expansion should be considered as an impact factor when designing the air gap length.